Swash-plate compressor and its housing

ABSTRACT

This swash-plate compressor ( 10 ) has a housing ( 12 ). The housing comprises a top portion ( 26 ) defining a passage ( 32 ) for a mixed gas of a refrigerant and lubricating oil to be introduced into its interior, and a valve ( 45 ) such as a solenoid valve attached to the top portion. The top portion ( 26 ) has at least one barrier ( 42 ) which is provided within the passage and with which the mixed gas can collide, a recess ( 44 ) for reserving the lubricating oil in the mixed gas which flows down, and a hole ( 46 ) communicating between the recess and the inner space of the housing. The valve opens and closes this hole.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a swash-plate compressor to be used for an automobile air-conditioning system.

[0003] 2. Description of the Related Art

[0004] In a swash-plate compressor, one of compressors incorporated into an automobile air-conditioning system to perform a compressing operation, rotation of a shaft to be driven to rotate when subjected to rotational power of a vehicle engine is converted into reciprocation of a plurality of pistons disposed around the shaft in parallel thereto.

[0005] In the swash-plate compressor, to perform this conversion of motions, a circular swash plate is attached to the shaft so as to diagonally intersect the shaft, and each piston is provided with a recess for receiving a part of the swash plate, each piston and the swash plate being brought into contact through bearing members disposed in the recess of each piston.

[0006] In the swash-plate compressor, when its operation is started, evaporating ingredients of lubricating oil stored on the bottom of its housing and a part of mixed gas of a refrigerant and the lubricating oil to be introduced into the swash-plate compressor through a passage provided on the top inside the housing respectively enter the recess of each piston to serve for lubrication between the swash plate and the bearing members.

[0007] Actually, however, there were cases where supply of the lubricating oil to a portion between the swash plate and the bearing members was insufficient, causing seizure between the swash plate and the bearing members shortly after starting, and causing the swash-plate compressor to stop operating.

[0008] In view of this, it has been proposed to add another supply route of the lubricating oil. This supply route includes a screw hole provided at the shaft and opening at its one end as well as a plurality of holes communicating with the screw hole and opening toward the thrust bearing (Japanese Patent Appln. Public Disclosure No. 6-101641).

[0009] According to this, after the swash-plate compressor starts its operation, the evaporating ingredients of the lubricating oil on the bottom of the housing and the lubricating oil ingredients in the mixed gas flow into the screw hole opening at one end of the shaft to be led from the screw hole through the screw hole into the portion between the swash plate and the bearing portion to be supplied. Even by this, however, the lubricating oil is not sufficiently refilled, thereby sometimes causing seizure.

SUMMARY OF THE INVENTION

[0010] An object of the present invention is to provide a structure for introducing a large quantity of lubricating oil into recesses of pistons which receive a part of the swash plate of a swash-plate compressor.

[0011] This invention relates to a housing for a swash-plate compressor which comprises: a top portion defining a passage for a mixed gas of a refrigerant and lubricating oil to be introduced into the swash-plate compressor and a valve such as a solenoid valve attached to the top portion. The top portion has at least one barrier with which the mixed gas can collide, a recess for reserving the lubricating oil in the mixed gas adhering to the barrier by collision with the barrier and flowing down along the barrier, and a hole communicating with the recess and the inner space of the housing. The valve performs opening and closing of the hole.

[0012] The swash-plate compressor comprises the housing, a cylinder block housed in the inner space of the housing and provided with a plurality of cylinders at intervals from each other about the axis of the cylinder block and openings each communicating with one of the cylinders, a shaft rotatably supported on the cylinder block, a swash plate secured to the shaft and rotatable with the shaft, and a piston disposed inside each cylinder of the cylinder block and having a cavity to receive a part of the swash plate.

[0013] According to the present invention, by absorption of the mixed gas from the exterior of the housing toward its interior, the mixed gas is introduced into a passage of a top portion of the housing and floats in the passage. At this time, a part of the mixed gas collides with a barrier in the passage, causing its lubricating oil ingredient to adhere to the barrier. The lubricating oil adhered to the barrier flows down into a recess of the passage along the barrier. Consequently, during operation of the swash-plate compressor, the lubricating oil ingredients are reserved inside the recess.

[0014] By operating the valve to open a hole communicating with the recess, the lubricating oil reserved in the recess can be made to run down through the hole communicating with the recess. The lubricating oil running down from the hole goes down on a cylinder block which occupies the inner space of the housing, flows into one or plural cylinders through an opening in the peripheral wall face of the cylinder block, goes down the peripheral face of a piston inside the cylinder, and reaches the inside of a cavity of the piston. If one of the openings of the cylinder block is disposed to confront the hole of the housing top, the lubricating oil running down reaches the inside of the cylinder directly through the opening.

[0015] Consequently, by opening the valve, for example, prior to activation of the swash-plate compressor, a large quantity of oil previously stored in the housing top can be supplied to a contact portion of the swash plate and the bearing member, thereby preventing generation of seizing in the contact portion of the swash-plate compressor to be subsequently activated.

[0016] When a solenoid valve is used as the valve, it is possible to electrically control opening and closing of the hole to fit to the starting time of the swash-plate compressor.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a partial vertical section of the swash-plate compressor according to the present invention.

[0018]FIG. 2 is a cross section obtained along the line 2-2 of FIG. 1.

[0019]FIG. 3 is a cross section obtained along the line 3-3 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Referring to FIGS. 1 and 2, a swash-plate compressor to be loaded on an automobile is generally shown by a reference numeral 10.

[0021] The swash-plate compressor 10 comprises a housing 12, a cylinder block 14 housed in the inner space of the housing 12, a shaft 16 rotatably supported on the cylinder block 14, a swash plate 18 secured to the shaft 16, and a plurality of pistons 22 respectively disposed within a plurality (five in the illustrated embodiment) of cylinders 20 provided in the cylinder block 14 to extend in its axial direction.

[0022] The swash-plate compressor 10 is driven when subjected to rotational power of an on-vehicle engine (not shown). The rotational power is transmitted to the shaft 16 through a belt (not shown) to rotate the shaft. For transmission of the rotational power to the shaft 16 as well as its cancellation, a clutch apparatus (not shown) is attached to the front end portion of the shaft 16.

[0023] The rotation of the shaft 16 is converted into linear motion to reciprocate the piston 22 within each cylinder 20 in its axial direction. As a result, the mixed gas of the refrigerant and the lubricating oil is sucked into the cylinder 20 from its both ends by turns (see the chain line showing an outline of the moving route), the mixed gas is compressed inside the cylinder 20 and then exhausted to the outside from both ends of the cylinder 20 by turns (see the dotted line showing an outline of the moving route). In this process, the swash-plate compressor 10 performs compressing work in an automobile air-conditioning system.

[0024] The housing 12 comprises a body 24 which defines a housing space of the cylinder block 14 and having a generally cylindrical inner face, a top portion 26 following an upper portion of the body 24 to project upward therefrom, a tubular portion 28 with a reduced diameter following one end portion in the axial direction of the body 24 and projecting from the one end portion to surround the front end portion of the shaft 16, and a cap 30 secured to and covering an open end portion (the other end portion) of the body 24.

[0025] The housing 24 has in its upper and lower portions two cavities communicating with the housing space of the cylinder block 14 (however, only the upper cavity 31 is shown). Both cavities are substantially in the intermediate part of both end portions of the body 24 and positioned right above and right below the cylinder block 14.

[0026] The upper cavity 31 of the housing body receives the mixed gas to be introduced through a passage 32 mentioned later of the housing top 26 and serves to distribute it toward both ends of each cylinder 20. On the other hand, the cavity in the bottom portion acts as an oil pan which can store the lubricating oil.

[0027] The housing top 26 defines the passage 32 for the mixed gas to be introduced into the swash-plate compressor. The passage 32 begins with an opening 34 provided at the top portion 26 (in more detail, a cover 40 to be described later) and opening in the exterior of the housing 12 and ends with another opening 36 provided in the housing body 24 and opening into the upper cavity 31. Consequently, the mixed gas is introduced from the opening 34 into the passage 32 and can move from the other opening 36 through the passage 32 into the housing body 24.

[0028] In the illustrated embodiment, the top portion 26 has a generally rectangular plane shape (see FIG. 3) and includes side walls 38 extending upward from the housing body 24 and having a rectangular cross sectional shape, and a cover 40 which covers the open top face of the side walls and closes and which is secured to the side walls 38 so as to be integral with the side walls 38. Consequently, the housing body 24 also defined a part of the top portion 26. The top portion 26 may have another plane shape, for example, such as a polygonal and a circular shapes in place of the illustrated rectangular shape.

[0029] Inside the passage 32 there are provided at least one (four in the drawings) barrier 42, a recess 44 and a hole 46.

[0030] The four barriers 42 are arranged at intervals from each other between both ends 34, 36 of the passage 32. Each barrier 42 extends vertically upward from the housing body 24 toward the cover 40 and ends immediately before reaching the cover 40. Therefore, the mixed gas to be introduced into the passage 32 during operating of the swash-plate compressor 10 collides with each barrier 42 while passing through the passage 32 and flows through a clearance between each barrier 42 and the cover 40. When the mixed gas collides with the barrier 42, a part of the lubricating oil which is an ingredient of the mixed gas adheres to the barrier 42. Then, the lubricating oil adhered to the barrier 42 flows down the barrier 42 along its wall face into the recess 44 to be stored in the recess 44.

[0031] The recess 44 is defined by a part of the side walls 38 of the top portion and the outermost barrier 42 close to the opening 36 in the housing body 24. The recess 44 can be formed, in place of this embodiment, by setting the thickness of a part of the housing body 24 larger and forming a sunken place therein.

[0032] Also, in the illustrated embodiment, the outermost barrier 42 extends from one side of confronting both wall faces of the side walls 38 of the top portion to the other side. On the other hand, the other three barriers 42 extend alternately from one of both the wall faces of the side walls 38 to portions immediately before the other, with clearances between these barriers 42 and the other side wall. Therefore, the lubricating oil stored in the recess 44 can move through the clearances to the portion between the barriers 42, thereby keeping constant the height of the level of the lubricating oil stored in the recess.

[0033] It is possible to make each barrier 42, in place of the illustrated embodiment, extend from the cover 40 in the opposite direction toward the housing body 24. Also, each barrier 42 may be made to extend not vertically but diagonally or with a curve.

[0034] The lubricating oil stored in the recess 44 can be exhausted out of the recess 44 through the hole 46. The hole 46 is formed in the housing body 24 and communicates with the recess 44 and the inner space of the housing body 24. Consequently, the lubricating oil in the recess 44 can be made to go down onto the cylinder block 14 within the housing body 24.

[0035] The hole 46 is opened and closed by operating a valve, preferably a solenoid valve 45. The solenoid valve 45 is secured to the cover 40. The solenoid valve 45 has a valve body 47 which can go up and down within the passage 32, and the valve body 47 opens or closes the hole 46 by its up-and-down action.

[0036] The valve body 47 can be made to go up and down by electrically controlling the solenoid valve 45. The solenoid valve 45 is preferably controlled to open the hole 46 by elevating the valve body 47 for several seconds before starting (activating) the swash-plate compressor 10 which had stopped for a long time. Instead of this, it is also possible to operate the solenoid valve 45 every time the swash plate compressor 10 is activated while an automobile is driven.

[0037] The hole 46 may be provided in an arbitrary position in the axial direction of the housing body 24 but is preferably provided in the central position in the axial direction of the housing body 24, as shown in the drawings. By this, the hole 46 can be made to be close or to oppose to an opening 62 to be described later which is provided in the cylinder block 14 and communicates with the cylinder 20.

[0038] According to this, the lubricating oil going down onto the cylinder block 14 runs down along the periphery of the cylinder block 14 and reaches the opening 62, or enters directly into the opening 62 as described later. Thereafter, the lubricating oil enters the cylinder 20, runs down along the periphery of the cylinder, and reaches a connecting portion (a boss 64 to be described later) between the shaft 16 and the swash plate 18 within the cavity 70 to be described later of the piston 22.

[0039] A plurality of cylinders 20 provided in the cylinder block 14 are arranged at intervals from each other about the axis of the cylinder block 14. Each cylinder 20 opens at both ends of the cylinder block 14, and both ends of the cylinder 20, i.e., both ends of the cylinder block 14 are respectively brought into contact with a cap 30 of the housing and one end portion of the housing body 24 through a pair of valve plates 48, 50.

[0040] The housing cap 30 and the one end portion of the housing body 24 respectively have two concentric annular spaces (only annular spaces 52, 54 provided in the cap 30 are shown) confronting both valve plates 48, 50.

[0041] Of both annular spaces, the inner annular space 52 communicates with the upper cavity 31 of the housing body and can receive the mixed gas. On the other hand, the outer annular space 54 can receive the mixed gas discharged out of the cylinder 20. For reference, the letters L and H respectively meaning low pressure and high pressure are put in the annular spaces 52, 54.

[0042] In both valve plates 48, 50, respectively, there are provided two holes 56, 58 allowing the mixed gas to move between the annular spaces 52, 54 and each cylinder 20. In each hole, a check valve (not shown) to control flowing of the mixed gas is disposed. Further, both annular spaces on the high pressure side (H) of the housing body 24 communicate with each other through a tube (not shown) inserted into a hole penetrating the cylinder block 14 in its axial direction.

[0043] The mixed gas discharged into the annular space on the high pressure side is exhausted outside the housing 12 from an outlet 60 provided in the cap 30 of the housing and communicating with the annular space 54 on the cap side.

[0044] The cylinder block 14 is provided with an elongated opening 62 communicating with each cylinder 20. Each opening 62 is placed substantially in the central portion of each cylinder 20 in its axial direction. In the illustrated embodiment, one cylinder 20 is placed uppermost with its opening 62 confronting the hole 46 for the lubricating oil. Therefore, the lubricating oil flowing down from the hole 46 drops directly into the opening 62.

[0045] The swash plate 18 for converting the rotation of the shaft 16 into the reciprocation of each piston 22 includes a boss portion 64 surrounding the shaft 16 and secured thereto, and a disk portion 66 extending from the boss portion. The reference numeral 68 shows a pair of thrust bearings disposed in contact with both ends of the boss portion 64 to surround the shaft 16.

[0046] The disk portion 66 of the swash plate is inclined to the shaft 16. That is, the disk portion 66 forms a crossed axes angle other than 90° relative to the shaft 16. Therefore, when the swash plate 18 rotates together with the shaft 16, an arbitrary portion relative to the circumferential direction of the disk portion 66 in contact with each piston 22 changes with respect to the axial direction of the shaft 16. As a result, each piston 22 receives axial force from the disk portion 66.

[0047] Each piston 22 disposed within each cylinder 20 of the cylinder block has a cavity 70 for receiving the disk portion 66 of the swash plate 18.

[0048] In each cavity 70, there are disposed a disk-like shoe 72 which is a bearing member in contact with each face of the disk portion 66, and a ball 74 rotatably held on the shoe 72 and the wall face which defines the cavity 70. The disk portion 66 is brought into contact with each piston 22 (in more detail, with the wall face of the cavity 70).

[0049] Consequently, when the swash plate 18 rotates, each piston 22 in contact with the disk portion 66 is forced to displace, thereby to reciprocate.

[0050] Prior to starting of the swash-plate compressor 10, a large quantity of the lubricating oil which flows down onto the opening 62 of the cylinder from the top portion 26 of the housing and arrives onto the boss 64 within the cavity 70 of the piston 22 inside the cylinder moves along the disk portion 66 in its radial direction when the swash-plate compressor 10 starts, and reaches the portion between the disk portion 66 and the shoe 72 to lubricate them. As a result, a shortage of the lubricating oil caused during stoppage of operation of the swash-plate compressor 10 and seizure accompanying thereto between the disk portion 66 and the shoe 72 are solved. 

What we claim is:
 1. A housing for a swash-plate compressor, comprising: a top portion defining a passage for a mixed gas of a refrigerant and lubricating oil to be introduced into said swash-plate compressor; and a valve attached to said top portion; wherein said top portion has at least one barrier which is provided within said passage and with which said mixed gas can collide; a recess for reserving said lubricating oil within said mixed gas adhered to said barrier by the collision and flowing down along said barrier; and a hole communicating with said recess and an inner space of said housing, and wherein said valve performs opening and closing of said hole.
 2. A housing according to claim 1 wherein said valve is formed from a solenoid valve.
 3. A compressor comprising: a housing described in claim 1; a cylinder block accommodated in the inner space of said housing, said cylinder block including a plurality of cylinders at intervals from each other about its axis and an opening communicating with each cylinder; a shaft supported rotatably on said cylinder block; a swash plate secured to said shaft and rotatable with said shaft; and a piston disposed within each cylinder of said cylinder block and having a cavity for receiving a part of said swash plate.
 4. A housing according to claim 3 wherein said valve is formed from a solenoid valve.
 5. A compressor according to claim 3 wherein one of the openings of said cylinder block and the hole on said top portion of said housing confront each other. 